LOS ANGELES — At a time when random drug testing is part of the job for pilots, train operators, police officers and firefighters — to name a few — one high-profile line of work has managed to remain exempt: doctors.

That might be about to change. California would become the first state to require doctors to submit to random drug and alcohol tests under a measure to appear on the ballot this November.

The proposal, which drew approval in early focus groups, was inserted as a sweetener in a broad initiative pushed by trial lawyers that also includes an unrelated measure to raise the state’s financial cap on medical-malpractice awards for the first time since 1975, to $1.1 million from $250,000. In California, it is permissible to bundle various measures into one ballot initiative, as long they address a single subject.

The stage has thus been set for a battle being closely watched by doctors across the country. The medical industry, including doctors, hospitals and medical-insurance companies, has raised more than $35 million to fund an attempt to defeat it.

Lawyers, aligned with some consumer-watchdog groups, say they cannot match that spending, but they have signaled an equally aggressive campaign with YouTube videos asking why doctors should not have to “pee in a cup” when firefighters and pilots do.

Given its potential to set a national precedent and the provocative questions it raises — substance abuse is a well-known problem in the medical profession — Proposition 46, as it is known, is drawing national attention and debate.

It has been endorsed by some of the state’s most powerful Democrats, including Sen. Barbara Boxer and Rep. Nancy Pelosi, the House minority leader. Its opponents include unions, the state Chamber of Commerce and the California chapter of Planned Parenthood, which fears Proposition 46 would drive OB-GYN doctors into fields of medicine less subject to risk of litigation.

The drug-testing provision, its sponsors said, is an inducement that bubbled up in the course of a focus group of voters testing arguments that could persuade people to support a higher damage ceiling in malpractice lawsuits.

Under Proposition 46, the ceiling for pain-and-suffering awards in medical-negligence suits, set at $250,000 by the state Legislature in 1975, would be raised to $1.1 million to reflect inflation.

The results of random drug tests on doctors would be reported to the California Medical Board; hospitals would be required to report the names of doctors suspected of abusing drugs or alcohol. Doctors would also be required to consult state prescription databases before prescribing controlled substances to patients, to guard against “doctor shopping.”

Doctors predicted voters would see through what they called political trickery. Dr. Richard Thorp, president of the California Medical Association, described the measure as a “money grab by trial lawyers.” He added: “The decision about drug and alcohol testing shouldn’t be made by political consultants — it should be made by stakeholders in a careful, thoughtful way.”

Asked if California doctors could support drug testing in any form, Thorp said: “That’s a great theoretical question. But we’re not dealing with a theatrical initiative. We are dealing with this state initiative. We cannot pass this initiative as it is written today. It is a flawed, deceptive ballot initiative, with one goal in mind: to increase money for trial lawyers.”

Still, the measure threatens to put the medical profession in the difficult position of having to argue against the kind of scrutiny that an increasing number of workers — particularly in jobs affecting the public well-being — routinely undergo. Backers of Proposition 46 have begun putting out a steady stream of news releases about cases involving doctors with a history of drug and alcohol abuse.

“It’s crucial: I can’t believe we haven’t done this already,” said Arthur Caplan, a medical ethicist at New York University. “We can argue about how often that is and what to do if you (test) positive. But the idea that we wouldn’t be screening our surgeon, our anesthesiologist or our oncologist when we are going to screen our bus drivers and our airline pilots strikes me as ethically indefensible.”

Daniel Levinson, the inspector general for the Department of Health and Human Services, said there should be random drug testing across the medical profession. “I don’t think that a carve-out when it comes to the medical field is sensible public policy,” he said. “No one should be above suspicion or below suspicion. I think we all need to play by similar rules.”